1. Field of the Invention
The present invention relates to a mobile robot, and more particularly, to a mobile robot charge station return system, which may return a mobile robot to a charge station exactly and rapidly according to a charge station position guidance signal emitted from the charge station.
2. Description of the Related Art
Robots have been developed for industrial purposes, which have been used for factory automatization, or for gathering or collecting information in a limited environment in which persons is unbearable, in stead of persons. Recently, such a robot-engineering field has been increasingly developed through the use in the most up-to-date space development industry, which results in development of a human-friendly home robot. The representative example of such a human-friendly home robot is a cleaning robot.
A cleaning robot, which belongs to a mobile robot, is an apparatus inhaling dust or foreign substance while traveling a certain cleaning area such as a house and an office. Such a cleaning robot includes travel means having right and left wheel motors for moving the corresponding cleaning robot, a plurality of sensors for detecting obstacles so that it can move without collision with various obstacles within a cleaning area, a controller for generally controlling the cleaning robot, etc., in addition to elements of a general vacuum cleaner inhaling dust or foreign substance.
On the other hand, a mobile robot has an automatic charge function because it carries out its own duties while moving a predetermined area. That is, the mobile robot automatically returns to a chare station installed in a predetermined position within the area and charges its own battery when it checks the battery level by itself and the battery level does not reach a reference value. After charging the battery, the mobile robot carries out its own duties again.
According to the prior art, in order to cause the mobile robot to automatically return to a chare station, a method has been used, which randomly moving the mobile robot along the wall surface of the area, and causing the mobile robot to return to the chare station when an artificial mark attached to the chare station is detected.
However, since such a method randomly moves the mobile robot along a wall surface, time required for returning to a chare station changes depending on areas in which the mobile robot is located. Further, according to this method, when the artificial mark attached to the chare station is detected late, the operation of the mobile robot may be stopped due to the consumption of the battery thereof.
According to another method for automatically causing a mobile robot to return to a chare station, signal emission means for emitting infrared rays or supersonic waves is installed in the chare station, and the mobile robot is allowed to return to the chare station when the infrared rays or supersonic waves emitted from the signal emission means are detected.
However, the conventional mobile robot can calculate only direction information of a charge station but cannot calculate distance information to the charge station from a signal emitted from the charge station. Accordingly, it is difficult to modify a charge station return path until the mobile robot mechanically or electrically contacts with the charge station.